1. Priority Claim
This application claims the benefit of priority from European Patent Application No. 05011637.5, filed May 30, 2005, which is incorporated by reference herein.
2. Technical Field
The invention relates to an image processor and more specifically to an image processing system capable of performing alpha-blending.
3. Related Art
Vehicle information and entertainment systems and consumer entertainment devices may employ sophisticated graphical schemes. A vehicle information and entertainment system may display car navigation data, while transmitting video information and image elements of a graphical user interface.
An image may be blended from image layers. A blended image may include different image elements visible against a background image. An image layer may be used as a background image on an image layer. An α-layer may also be used. The α-layer may be associated with an image layer to assign a transparency value to image elements.
In image blending, an image layer may include an α-layer indicating a transparency of the image. It may be possible to semi-transparently overlay image elements on a background image. For an image element, a corresponding α-layer element may specify an image element as opaque. Another image element may be determined by an α-layer element to be semi-transparent. A remaining area of the image layer may be transparent. An image element in the blended image may be displayed as opaque in front of a background image. In some screens, another image element may be visible as semi-transparent in front of the background image.
An α-blending may create dynamic image effects such as a fade-in/fade-out of image elements. Such effects may be applied to elements of a graphical user interface to give the graphical user interface a more sophisticated appearance.
Vehicle information and entertainment systems and consumer entertainment devices may employ complex graphic controllers. These graphic controllers generate images to be displayed from image layers. The layered images allow independent control of different image elements of a complex blended image.
Graphic controllers that perform image overlay and blending processing may be expensive. Graphic controllers may be designed as a general-purpose device to meet the requirements of some graphic applications. However, a specific application may use only a fraction of their functionalities. Such graphic applications that use an overlay and blending functionality may not use a general-purpose graphic controller efficiently. Therefore, a need exists for a system that overlays and blends efficiently.